It is believed that peptic ulcers such as gastric and duodenal ulcers are formed when aggressive factors such as acid and pepsin and protective factors such as mucosa-resistance, mucus, blood and duodenal control are out of balance and thus autolysis is induced.
Peptic ulcers are to be medically treated as a rule. Therefore medicinal treatments therefor have been attempted so far. Examples of the antiulcer drugs which are commonly used today include cimetidine and ranitidine, each based on the histamine H.sub.2 receptor antagonism. However it has been reported that these drugs are accompanied by some side effects, for example, an antiandrogenic effect or an inhibitive effect on hepatic metabolic enzyme activity.
Under these circumstances, it is recently suggested that an inhibitor for H.sup.+ --K.sup.+ ATPase, which specifically occurs in gastric wall cells, would serve as an excellent inhibitor for acid secretion.